Day 9 is cardio in sequence: 10 step jacks, 6 side jacks, 10 step jacks, 6 side jacks - four rounds down the card, and the whole list is one set. Rest 2 minutes, then 3, 5 or 7 sets by level. Two jacks you already know, alternating without a pause.
Step jacks step out wide with the hands coming together overhead; side jacks step to the side with the same-side arm arcing over the head. Ten of the first, six of the second, four times over: sixty-four stepped reps in a row per set. The step jack is the workhorse and the side jack is the change of direction, and moving between them without stopping keeps the heart rate steady rather than letting it spike and fall.
Keep the arms fully involved - overhead reach on step jacks, a proper arc over the head on side jacks - because the arms are what turn stepping into cardio. Land softly, knees loose, and keep the pace even from round one to round four rather than fast at the start and slow at the end.
Four rounds and no pause - Day 9 asks for rhythm, and rhythm is what your body is learning.
Make it Harder: Take the side jacks up to 10 per round to match the step jacks.
Make it Easier: Do 3 rounds instead of 4 and rest as written.
